<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>后代选择器</title>
    <style>
        p{
            color: blueviolet;
        }
        div p {
            font-size: 50px;
        }
        .box1 .box2 p {
            border:10px  solid #000;
        }
        div,p{
            font-size: 30px;
        }
    </style>
</head>
<body>
    <p>我是外边的p评标</p>
    <div>
        <p>我是内部的p标签</p>
    </div>
    <p>我是外边的p评标</p>
</body>
</html>